I love this bra. It is super soft and fits well. I am a 32DDD (28.5 inch underbust) and I bought a Small. This bra provides enough coverage but is small enough around the band to fit snuggly on my ribs. Normally I have to buy small sports bras to fit my ribs but then my boobs spill out everywhere. Not anymore! I Will be buying more in other colors. Note: I do not run, so I cannot speak to the type of support it may provide for that. Also, if your underbust is more than 28.5 inches I would size up. If it were any tighter I would have back fat and side boob spilling out.